1. Field of the Invention
The invention relates to high impact thermoplastic molding materials comprising modified polyphenylene ethers, polyoctenylenes and polyamides.
2. Discussion of the Background
Polyphenylene ethers (PPE) are technical high-performance thermoplastics with high melting viscosities and softening points. They are suitable for numerous technical applications in which durability at high temperatures is important (see U.S. Pat. Nos. 3,306,874; 3,306,875; 3,257,357 and 3,257,358).
Certain characteristics of polyphenylene ethers are undesirable for technical applications. For example, molded elements made from polyphenylene ethers are brittle because of their poor impact resistance. Also disadvantageous are the high melting viscosities and softening points which lead to difficulties in handling. It must also be considered that polyphenylene ethers tend to discolor and are unstable at high temperatures. Polyphenylene ethers are soluble in many organic solvents or swell exceedingly. This results in their being unsuitable for applications in which they come into contact with such solvents.
It is known that the characteristics of PPE can be improved by mixing it with other polymers. Thus, for example, mixtures with high impact polystyrenes have achieved great technical significance (see DE-PS No. 21 19 301 and PS No. 22 11 005). These mixtures can be easily made into molded elements with sufficient impact resistance, but exhibit the disadvantage that as the polystyrene content increases, its ability to withstand hot forming decreases. The resistance of these mixtures to solvents is also unsatisfactory.
Mixtures of polyphenylene ethers with polyamides do have good flow capability and also good solvent resistance (DE-AS No. 16 94 290, JP-A No. 78 47 390). However, the resulting products are generally brittle, because the two components are incompatible and therefore disperse through each other poorly. Aromatic polyamides, such as those employed, for example, according to EP-OS No. 0 131 445 also work poorly with polyphenylene ethers. Better compatibility of the two phases is achieved through a functionalization of the polyphenylene ether, for example with maleic anhydride in the presence of radical initiators (JP-OS No. 84/066 452). The use of radical initiators, however, leads to an undesirable and uncontrolled partial gelling of the PPE-phase.
It has therefore been suggested to increase the compatability of both polymers by adding an adequate quantity of a liquifying agent, such as an organic phosphate (see EP-OS No. 0 129 825) or a diamide (see EP-OS No. 0 115 218). Such solutions are not adequate, however, because the improved compatability must be obtained at the cost of significantly reduced hot forming resistance. Molding materials to which copolymers of styrene and unsaturated acid derivatives have been added have the same disadvantage (see EP-OS No. 0 046 040).
The object of EP-PS No. 0 024 120 is resin materials consisting of a polyphenylene ether, a polyamide, a third component and perhaps high-molecular weight caoutchouc polymers. A liquid diene polymer, an epoxide or a compound with a double or triple bond and a functional group such as an acid, anhydride, ester, amino or alcohol group is employed as the third component. The strength of the resultant resin material, however, is inadequate for many applications.
Finally, German Patent Application No. P 35 45 249.8 discloses high impact thermoplastic materials from a remelted preforming material, a primarily aliphatic polyamide and other additives. The preforming material consists of polyphenylene ethers, polyoctenylenes, maleic anhydride and other acid components having a melting point below 100.degree. C. A disadvantageous of this method is that the maleic anhydride and the other acid components must be heated to such an extent that a uniform molten mass of the four components is produced. This results in potential health hazards.